The field of the disclosure is related to systems and methods for particle detection. More particularly, the disclosure is directed to systems and methods for ion detection using superconducting circuits.
Atom Probe Tomography (“APT”), a form of destructive time-of-flight (“TOF”) microscopy, is a technique in which atoms from a sample of interest are progressively evaporated off using an applied electric field and accelerated towards a detector positioned some distance away. By measuring the arrival time of the ionized atoms at the detector, it is then possible to compute the respective charge-to-mass ratio of the atoms, and identify the species of the atoms. Current atom probe detector technologies are based on a combination of a microchannel plate (“MCP”) positioned in front of a delay line anode. Incoming ions from the sample of interest enter capillaries etched in the MCP and impact the walls inside the capillary. Charged particle impacts on the side walls of the capillaries release secondary electrons, which are accelerated down the capillary and continue to generate additional electrons. In this way, the MCP acts as an amplifier, creating a much larger cloud of charges that then exits the backside of the MCP. The charge cloud then impinges upon a delay line anode positioned behind the MCP, generating a measurable signal pulse.
APT has particularly demanding requirements for the detectors. The main weaknesses that need to be addressed include detection efficiency, kinetic energy resolution, multi-hit discernment, and maximum event rate. Multi-hit discernment refers to the situation in which more than one atom evaporates at a time, thus creating two events in the detectors at the same time. With the current MCP and delay line anode readout it is possible to distinguish two hits if they are adequately separated in space and time. However, there is a strong correlation in double evaporation events such that the two ions impact the detector very near each other and at about the same time. This kind of event cannot be distinguished from a single ion event. Addressing detector limitations is critical to the advancement of APT.
In light of the above, there remains a need for efficient ion detectors for use in a variety of applications, including atom probe systems.